Systems and methods for the mitigation of hop

Abstract

A system for mitigating hop in a propelled machine is provided. A controller is operable to receive an aggressiveness command based on an operator input. A sensor is operable to measure a parameter indicative of hop and output a hop signal indicative of a magnitude of machine hop, based on the measurement. A manager is operable to reduce an aggressiveness indicated by the aggressiveness command in proportion to the indicated magnitude of machine hop.

1. A method for mitigating hop in a propelled machine, the method comprising:
 receiving an aggressiveness command based on an operator input, wherein the aggressiveness command indicates a desired speed ratio between two independently controllable transmissions of the propelled machine; 
 measuring a parameter indicative of hop, and determining a magnitude of machine hop based on the measurement; and 
 reducing an aggressiveness indicated by the aggressiveness command in proportion to the indicated magnitude of machine hop. 
 
   
   
     2. The method of  claim 1 , wherein determining a magnitude of machine hop includes determining a magnitude of resonant hop of the machine. 
   
   
     3. The method of  claim 1  wherein reducing the aggressiveness includes:
 comparing the magnitude of machine hop to a hop tolerance; and 
 reducing the aggressiveness indicated by the aggressiveness command in proportion to an amount, if any, by which the magnitude of machine hop exceeds the hop tolerance. 
 
   
   
     4. The method of  claim 1 , wherein reducing the aggressiveness includes:
 performing a proportional-integral-derivative control algorithm based on the magnitude of machine hop; and 
 using an output of the proportional-integral-derivative control algorithm to limit the aggressiveness command. 
 
   
   
     5. A method for mitigating hop in a propelled machine, the method comprising:
 receiving an aggressiveness command based on an operator input; 
 measuring a parameter indicative of hop, wherein measuring a parameter indicative of hop includes measuring a parameter indicative of at least one of: speed of a front wheel of the machine, pressure in a clutch configured to drive a front wheel of the machine, pressure in a transmission configured to drive a front wheel of the machine, torque output of a transmission configured to drive a front wheel of the machine, acceleration of a front portion of the machine, and pressure in a lift cylinder of an implement of the machine; 
 determining a magnitude of machine hop based on the measurement; and 
 reducing an aggressiveness indicated by the aggressiveness command in proportion to the indicated magnitude of machine hop. 
 
   
   
     6. A method for mitigating hop in a propelled machine, the method comprising:
 receiving an aggressiveness command based on an operator input; 
 measuring a parameter indicative of hop, wherein measuring a parameter indicative of hop includes providing a sensor configured to output a hop signal indicative of a magnitude of machine hop; 
 determining a magnitude of machine hop based on the measurement, wherein determining a magnitude of machine hop includes determining a magnitude of resonant hop of the machine and wherein determining a magnitude of resonant hop of the machine includes passing the hop signal through a bandpass filter; and 
 reducing an aggressiveness indicated by the aggressiveness command in proportion to the indicated magnitude of machine hop. 
 
   
   
     7. The method of  claim 6 , wherein the bandpass filter has a center frequency at or near a frequency of resonant hop of the machine. 
   
   
     8. The method of  claim 6 , wherein the bandpass filter has a center frequency between approximately 2 Hz and approximately 3 Hz. 
   
   
     9. A method for mitigating hop in a propelled machine, the method comprising:
 receiving an aggressiveness command based on an operator input; 
 measuring a parameter indicative of hop, wherein measuring a parameter indicative of hop includes providing a sensor configured to output a hop signal indicative of a magnitude of machine hop; 
 determining a magnitude of machine hop based on the measurement, wherein determining a magnitude of machine hop includes determining a magnitude of resonant hop of the machine and wherein determining a magnitude of resonant hop of the machine includes determining a power of the hop signal at a particular frequency; and 
 reducing an aggressiveness indicated by the aggressiveness command in proportion to the indicated magnitude of machine hop. 
 
   
   
     10. The method of  claim 9 , wherein the particular frequency is at or near a frequency of resonant hop of the machine. 
   
   
     11. The method of  claim 9 , wherein the particular frequency is between approximately 2 Hz and approximately 3 Hz. 
   
   
     12. A system for mitigating hop in a propelled machine, the system comprising:
 a controller operable to receive an aggressiveness command based on an operator input, wherein the aggressiveness command indicates a desired speed ratio between two independently controllable transmissions of the propelled machine; 
 a sensor operable to measure a parameter indicative of hop and output a hop signal indicative of a magnitude of machine hop, based on the measurement; and 
 a manager operable to reduce an aggressiveness indicated by the aggressiveness command in proportion to the indicated magnitude of machine hop. 
 
   
   
     13. The system of  claim 12 , wherein the hop signal is indicative of a magnitude of resonant hop of the machine. 
   
   
     14. The system of  claim 12 , further including a detector operable to compare the hop signal to a hop tolerance; and
 wherein the manager is operable to reduce an aggressiveness indicated by the aggressiveness command in proportion to an amount, if any, by which the magnitude of machine hop exceeds the hop tolerance. 
 
   
   
     15. The system of  claim 12 , further including:
 a proportional-integral-derivative controller operable to calculate a hop-limited aggressiveness command based on the magnitude of machine hop, the manager operable to override the aggressiveness command based on operator input with the hop-limited aggressiveness command. 
 
   
   
     16. A system for mitigating hop in a propelled machine, the system comprising:
 a controller operable to receive an aggressiveness command based on an operator input; 
 a sensor operable to measure a parameter indicative of hop and output a hop signal indicative of a magnitude of machine hop, based on the measurement, wherein the sensor is operable to measure a parameter indicative of at least one of: speed of a front wheel of the machine, pressure in a clutch configured to drive a front wheel of the machine, pressure in a transmission configured to drive a front wheel of the machine, torque output of a transmission configured to drive a front wheel of the machine, acceleration of a front portion of the machine, and pressure in a lift cylinder of an implement of the machine; and 
 a manager operable to reduce an aggressiveness indicated by the aggressiveness command in proportion to the indicated magnitude of machine hop. 
 
   
   
     17. A system for mitigating hop in a propelled machine, the system comprising:
 a controller operable to receive an aggressiveness command based on an operator input; 
 a sensor operable to measure a parameter indicative of hop and output a hop signal indicative of a magnitude of machine hop, based on the measurement, wherein the hop signal is indicative of a magnitude of resonant hop of the machine; 
 a bandpass filter operable to limit the bandwidth of the hop signal,; 
 a detector operable to compare the magnitude of the bandwidth-limited hop signal to a hop tolerance; and 
 a manager operable to reduce an aggressiveness indicated by the aggressiveness command in proportion to the indicated magnitude of machine hop. 
 
   
   
     18. The system of  claim 17 , wherein the bandpass filter has a center frequency at or near a frequency of resonant hop of the machine. 
   
   
     19. The system of  claim 17 , wherein the bandpass filter has a center frequency between approximately 2 Hz and approximately 3 Hz. 
   
   
     20. A system for mitigating hop in a propelled machine, the system comprising:
 a controller operable to receive an aggressiveness command based on an operator input; 
 a sensor operable to measure a parameter indicative of hop and output a hop signal indicative of a magnitude of machine hop, based on the measurement, wherein the hop signal is indicative of a magnitude of resonant hop of the machine; 
 a transform function operable to determine a power of the hop signal proximate a particular frequency; and 
 a manager operable to reduce an aggressiveness indicated by the aggressiveness command in proportion to the power of the hop signal. 
 
   
   
     21. The system of  claim 20 , wherein the particular frequency is at or near a frequency of resonant hop of the machine. 
   
   
     22. The system of  claim 20 , wherein the particular frequency is between approximately 2 Hz and approximately 3 Hz. 
   
   
     23. A propelled machine having front and rear wheels, the propelled machine comprising:
 an AWD system; 
 a controller operable to receive an aggressiveness command based on an operator input and to drive front wheels of the machine at a speed related to a speed of rear wheels of the machine, based on the aggressiveness command; 
 a sensor operable to measure a parameter indicative of hop and output a hop signal indicative of a magnitude of machine hop, based on the parameter; and 
 a manager operable to reduce an aggressiveness indicated by the aggressiveness command in proportion to the indicated magnitude of machine hop. 
 
   
   
     24. The propelled machine of  claim 23 , wherein the aggressiveness command indicates a desired speed ratio between two independently controllable transmissions of the propelled machine. 
   
   
     25. The propelled machine of  claim 23 , wherein the sensor is operable to measure a parameter indicative of at least one of: speed of a front wheel of the machine, pressure in a clutch configured to drive a front wheel of the machine, pressure in a transmission configured to drive a front wheel of the machine, torque output of a transmission configured to drive a front wheel of the machine, acceleration of a front portion of the machine, and pressure in a lift cylinder of an implement of the machine. 
   
   
     26. The propelled machine of  claim 23 , wherein the hop signal is indicative of a magnitude of resonant hop of the machine. 
   
   
     27. The propelled machine of  claim 26 , further including a bandpass filter operable to limit the bandwidth of the hop signal, the detector operable to compare the magnitude of the bandwidth-limited hop signal to the hop tolerance. 
   
   
     28. The propelled machine of  claim 27 , wherein the bandpass filter has a center frequency at or near a frequency of resonant hop of the machine. 
   
   
     29. The propelled machine of  claim 27 , wherein the bandpass filter has a center frequency between approximately 2 Hz and approximately 3 Hz. 
   
   
     30. The propelled machine of  claim 26 , further including a transform function operable to determine a power of the hop signal proximate a particular frequency, the manager operable to reduce an aggressiveness indicated by the aggressiveness command in proportion to the power of the hop signal. 
   
   
     31. The propelled machine of  claim 30 , wherein the particular frequency is at or near a frequency of resonant hop of the machine. 
   
   
     32. The propelled machine of  claim 30 , wherein the particular frequency is between approximately 2 Hz and approximately 3 Hz. 
   
   
     33. The propelled machine of  claim 23 , further including a detector operable to compare the hop signal to a hop tolerance; and
 wherein the manager is operable to reduce an aggressiveness indicated by the aggressiveness command in proportion to an amount, if any, by which the magnitude of machine hop exceeds the hop tolerance. 
 
   
   
     34. The propelled machine of  claim 23 , further including:
 a proportional-integral-derivative controller operable to calculate a hop-limited aggressiveness command based on the magnitude of machine hop, the manager operable to override the aggressiveness command based on operator input with the hop-limited aggressiveness command.